DISTANCES TRAVELLED 119 



under fair conditions to migrate only a short dis- 

 tance, while others which are forced, or choose, to 

 migrate, pass on to distant unoccupied areas for 

 winter. Mr. H. S. Swarth has shown an excellent 

 example of this in his discussion of the races of the 

 fox sparrow, of which there are sixteen forms rec- 

 ognized at present. Our familiar eastern bird nests 

 from northwestern Alaska to Labrador, and con- 

 centrates in winter in the southeastern portion of 

 the United States, so that it travels a long route 

 each year. On the west coast of North America 

 there are six subspecies of this bird which in summer 

 are established in definite breeding ranges from 

 Unimak Island, at the end of the Alaska Peninsula, 

 south to the region of Puget Sound. Beginning at 

 the north these forms are known as Passerella iliaca 

 unalaschcensiSy insularisy sinuosuy annectens^ town- 

 sendi andfuliginosa. (See Fig. 4.) The three north- 

 ern races, unalaschcensis^ insularis^ and sinuosa^ 

 which occupy complementary ranges extending 

 from the Alaska Peninsula east to the region of 

 Prince William Sound, migrate to a common 

 wintering ground in southern California. The 

 next form, annectens^ breeds in the Yakutat Bay 

 region of Alaska and winters almost entirely in the 

 coastal region of central California. The form known 

 as townsendiy which nests in the coast region of 

 southern Alaska, winters in the coast region of 



